I just checked the coil stops in my Williams Lady Luck .. had put a new full kit in it from PBR . The coil stops are the same as the other new Williams ones I bought from PBR a while ago. Swapped the right one with a new one and almost no buzz now (also slightly adjusted EOS gap ). The left one was almost falling out .. must have lost a screw  .. Swapped it anyway and the buzz is still there but about 50% of what it was . Don't have time to fiddle with it any more at the moment.

Cheers
Dave